In search for effective antidiabetic agents that simultaneously inhibit α-glucosidase and scavenge free radicals, Horsfieldia motleyi showed promising bioactivity according to the proposed criteria. Bioassay-guided isolation of pericarp extract yielded a new 4-arylflavan named myristinin G (6), whose gross structure and absolute configuration were verified by 2D NMR and electronic circular dichorism (ECD). Myristinin G (6) concomitantly inhibited α-glucosidases (IC50 107.0 and 126.9 μM) and free radicals (SC50 54.3 and 279.9 μM). Of interest, 6 inhibited sucrase through an uncompetitive manner, which is rare in nature.
Keywords: Myristicaceae; Myristinin; antioxidant; diabetes; flavan; i; α-glucosidase.